Ab initio study of the structural properties of acetonitrile–water mixtures

Chen, Jinfan; Sit, Patrick H.‐L.

doi:10.1016/j.chemphys.2015.05.022

Cited by 25 publications

(36 citation statements)

References 65 publications

(108 reference statements)

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“…Instead, the proton diffuses to the bulk solvent for the case with Co(dmgBF 2 ) 2 or to the side group of Co(dmgH) 2 through the extended water hydrogen bond network. 67 This difference between the gas-phase and the CPMD simulations highlights the key role of solvent molecules in the catalytic reaction cycle. The role of the water molecules as shuttles to aid the proton transfer process may lower its energy barrier, which was also observed in the previous DFT work.…”

Section: Discussion and Summarymentioning

confidence: 99%

Density Functional Theory and Car–Parrinello Molecular Dynamics Study of the Hydrogen-Producing Mechanism of the Co(dmgBF₂)₂ and Co(dmgH)₂ Cobaloxime Complexes in Acetonitrile–Water Solvent

Chen

Sit

2017

J. Phys. Chem. A

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The catalytic hydrogen-producing processes of two prototypical cobaloxime catalysts, Co(dmgBF) (dmgBF = difluoroboryl-dimethylglyoxime) and Co(dmgH) (dmgH = dimethylglyoxime), were studied by density functional theory (DFT) and Car-Parrinello molecular dynamics (CPMD) simulations in the explicit acetonitrile-water solvent. Our study demonstrates the key role of water molecules as shuttles to deliver protons to the cobalt active centers of these catalysts. However, the transfer of protons to the cobalt centers also competes with the diffusion of the proton away from the complex via the hydrogen bond network of water. Protons were found to react with the oxygen of the side group of Co(dmgH), while a similar reaction was not observed for Co(dmgBF). This explains the experimentally observed relative instability of Co(dmgH) in the acidic medium. The rate-limiting step of the hydrogen-producing process was found to be the first proton transfer to the cobalt center for both cobaloxime complexes. Structural and electron population analysis was carried out to provide insight into the origin of the difference of the proton transfer free-energy barriers of these two cobalt complexes. Our study has contributed to the key microscopic understanding of the hydrogen-producing process by this class of catalysts.

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Section: Discussion and Summarymentioning

confidence: 99%

Density Functional Theory and Car–Parrinello Molecular Dynamics Study of the Hydrogen-Producing Mechanism of the Co(dmgBF₂)₂ and Co(dmgH)₂ Cobaloxime Complexes in Acetonitrile–Water Solvent

Chen

Sit

2017

J. Phys. Chem. A

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“…ACN is structurally similar to methanol, but it is unable to donate hydrogen bonds; therefore, it is the perfect candidate to check if the hydrogen bond has a role in the LqE observation. Density fluctuations have been reported for aqueous mixtures of acetonitrile, − for which various groups have pointed out how water and acetonitrile do not homogeneously mix but rather organize themselves into water-rich and acetonitrile-rich regions percolating each other. For this system, the LqE is also observed, and it was analyzed in terms of concentration fluctuation parameters, Kirkwood–Buff integrals (KBIs) and/or Ornstein–Zernike (OZ) formalism.…”

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confidence: 99%

Inhomogeneity in Ethylammonium Nitrate–Acetonitrile Binary Mixtures: The Highest “Low q Excess” Reported to Date

Mariani

Ramondo

Salvitti

et al. 2017

J. Phys. Chem. Lett.

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The binary mixtures of the ionic liquid ethylammonium nitrate with acetonitrile have been studied by means of wide- and small-angle X-ray scattering and via two different computational methods, namely, classical molecular dynamics and DFT. The recently debated odd feature in the extreme low q region of some ionic liquid-based binary mixtures is linked to density fluctuations within the system. We show how the "low q excess" is due to some nanoscopic objects which are formed at certain compositions. These structures have different density with respect to the surrounding, thus generating the feature observed. Our results also show how the local arrangement is directly linked to the long-range structure. Moreover, we found once again a similarity in the physicochemical behavior of ethylammonium nitrate and water.

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“…Acetonitrile is an important aprotic polar solvent. Because of its excellent solubility and dielectric properties, it has been widely used in organic solvent research and electrochemical research . Acetonitrile molecules clustered, on the surface of Au electrode or platinum electrode, could form solvent layer, which has been obtained by modeling solvation.…”

Section: Introductionmentioning

confidence: 99%

Study on Preferential Solvation of Water by Electrochemical Method

et al. 2019

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The preferential solvation of water plays an important role in ferrocene research which is a subject of current interest. Voltammetric investigations were carried out for Au electrode in acetonitrile/water, showing preferential solvation of water. In our work, the preferential solvation of water in acetonitrile/water was studied by electrochemical methods including cyclic volitammetry, electrochemical impedance spectra and double‐step chronoamperometry. Ferrocenemethanol (FcCH2OH) molecules as a solute spontaneously adsorb on the electrode surface in anhydrous acetonitrile, resulting from acetonitrile molecules tend to form an acetonitrile solvent layer on the surface of the electrode and acetonitrile solvent layer has a lower energy barrier than the aqueous solvent layer, which has been obtained by modeling solvation. The solvent strongly influences electrochemical behavior of solute. Once there is an amount of water in acetonitrile solvent, FcCH2OH that adsorbed on the electrode surface desorb. This is because water preferentially solvate with FcCH2OH in term of intermolecular forces between solvent and solute. Moreover, hydrogen bond between water molecules and FcCH2OH molecules is stronger than dipole‐dipole interaction between acetonitrile molecules and FcCH2OH molecules in solvation effect. Through electrochemical behavior of FcCH2OH changing, preferential solvation of water is analyzed by electrochemical methods.

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Ab initio study of the structural properties of acetonitrile–water mixtures

Cited by 25 publications

References 65 publications

Density Functional Theory and Car–Parrinello Molecular Dynamics Study of the Hydrogen-Producing Mechanism of the Co(dmgBF₂)₂ and Co(dmgH)₂ Cobaloxime Complexes in Acetonitrile–Water Solvent

Density Functional Theory and Car–Parrinello Molecular Dynamics Study of the Hydrogen-Producing Mechanism of the Co(dmgBF₂)₂ and Co(dmgH)₂ Cobaloxime Complexes in Acetonitrile–Water Solvent

Inhomogeneity in Ethylammonium Nitrate–Acetonitrile Binary Mixtures: The Highest “Low q Excess” Reported to Date

Study on Preferential Solvation of Water by Electrochemical Method

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Ab initio study of the structural properties of acetonitrile–water mixtures

Cited by 25 publications

References 65 publications

Density Functional Theory and Car–Parrinello Molecular Dynamics Study of the Hydrogen-Producing Mechanism of the Co(dmgBF2)2 and Co(dmgH)2 Cobaloxime Complexes in Acetonitrile–Water Solvent

Density Functional Theory and Car–Parrinello Molecular Dynamics Study of the Hydrogen-Producing Mechanism of the Co(dmgBF2)2 and Co(dmgH)2 Cobaloxime Complexes in Acetonitrile–Water Solvent

Inhomogeneity in Ethylammonium Nitrate–Acetonitrile Binary Mixtures: The Highest “Low q Excess” Reported to Date

Study on Preferential Solvation of Water by Electrochemical Method

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Density Functional Theory and Car–Parrinello Molecular Dynamics Study of the Hydrogen-Producing Mechanism of the Co(dmgBF₂)₂ and Co(dmgH)₂ Cobaloxime Complexes in Acetonitrile–Water Solvent

Density Functional Theory and Car–Parrinello Molecular Dynamics Study of the Hydrogen-Producing Mechanism of the Co(dmgBF₂)₂ and Co(dmgH)₂ Cobaloxime Complexes in Acetonitrile–Water Solvent